Aperture Science, Inc., often referred to as Aperture Science or simply Aperture, is a United States-based scientific research corporation appearing in Portal and Portal 2, as well as other sources. Its main facility, the Aperture Science Enrichment Center, is located in Upper Michigan, while others can also be found in Cleveland, Ohio. Originally a shower curtain manufacturer named Aperture Fixtures, it evolved over the course of half a century into an experimental physics research institution and a bitter rival of Black Mesa.